Reserve Tiago Splitter added a season-high 23 points, many coming when the Spurs took charge late in the third and early in the fourth.

Rajon Rondo had 22 points and extended his consecutive streak of double-digit assist games to 35 with 15. Paul Pierce, who sprained his ankle in a 20-point loss at Detroit on Sunday, had 19 points.

DeJuan Blair chipped in with 12 points for the Spurs (9-3), but it was Parker winning the battle of elite point guards against Rondo that carried San Antonio.

Brandon Bass scored 16 and Kevin Garnett 14 for Boston (6-6), which managed just one offensive rebound and lost for the third time in four games.

The Spurs closed the third quarter with a 6-0 run, with Splitter getting a pair of baskets, to take an 82-74 lead.

They opened the fourth by scoring eight of the initial 10 points to open their biggest lead at that point, 90-76 on Splitter’s three-point play with just under 10 minutes to play.

Splitter’s two free throws increased it to 94-78 with 8:41 to go.

Boston closed the gap to nine, but the Spurs had a pair of easy driving baskets by Parker to maintain a comfortable margin.

That was until Rondo answered with a long jumper from the right corner off his own steal and a spinning bank shot, closing it to 104-98 with 3:17 left.

But that was as close as Boston would get.

Duncan had five points during a 9-0 spree that gave the Spurs a 69-60 edge midway into the third quarter. Boston then scored seven of the next nine, closing it to two on Pierce’s 3 from the right wing.

Rondo was responsible either with an assist, basket or pass for all the Celtics’ 23 points in the opening 8 1/2 minutes of the third quarter. He had eight assists, two baskets and fed Pierce, who got fouled in the lane before hitting two free throws.

In the quarter, the Celtics’ playmaker had eight assists and two baskets — accounting for all but one of Boston’s buckets — Jeff Green’s drive.

Neither team held more than a four-point lead until the Spurs scored 14 of the final 20 points in the first half to take a 56-48 edge into the break. Danny Green nailed a 3-pointer in the middle of the streak, giving him 30 straight games with at least one 3, the league’s longest current streak.